Preparation of Al 2O 3–ZrO 2–Ni nanocomposite by pulse electric current and pressureless sintering

Abstract

In the present study, dense Al 2O 3/(ZrO 2 + Ni) nanocomposites are prepared by pulse electric current sintering (PECS) at 1350 °C for 5 min or by pressureless sintering (PLS) at 1600 °C for 1 h. The nanometer-sized Ni particles (∼10 nm) were first introduced into the (Al 2O 3 + ZrO 2) powder mixtures by using a coating technique. The presence of the Ni particles prohibits the coarsening of the composite prepared by PLS; nevertheless, enhances the grain growth of the composites prepared by PECS. The sub-micrometer-sized ZrO 2 particle acts as microstructural stabilizer that slows down the coarsening of matrix grains in the composites prepared by both processes. Due to microstructural refinement, the strength of the Al 2O 3/(5%ZrO 2 + 1%Ni) nanocomposite is ∼40% higher than that of Al 2O 3 alone.